BF pauses FaceTime to text someone else

Hey, just wanting some advice. I’m currently in a LDR and BF and I FaceTime every night. Recently I’ve noticed that he’ll pause the FaceTime call and I can hear that he’s typing and he does it quite regularly throughout the call. I’m pretty sure he’s texting someone - probably a friend but it just bothers me. I trust him to be loyal and everything but I just think it’s kind of rude, disrespectful and it hurts. Like he’s on a call with me and not whoever he’s texting, they can wait. I want to talk to him about it but I don’t want to seem selfish and make a scene.